Human resource management is the most important factor in the organizational management in general and in the medium-sized comprehensive IT business in particular because human element is the original factor and the central factor as well in all the activities of the organization. In Vietnam, at the present, the number of the medium-sized comprehensive IT business is increasing more and more. However, the effectiveness of the human resource management has not met the need at all. The main purpose of this study was to find out the way to improve the human resource management in the medium-sized comprehensive IT business in Vietnam with the case study at VietSin Online Corporation. There are four specific objectives: (1) identifying the factors influencing the human resource management; (2) finding out the considerable differeneces of the factors that influence the human resource management; (3) investigating the current situation at VietSin Online Corporation to find out the advantages and weakpoints; and (4) suggesting the resolutions to improve and enforce the activities of human resource management of VietSin Online Corporation. The quantitative data of the research was collected and processed through the SPSS software version 14.0. And all the suggestions and recommendations are proposed in the solution part.